Seroatlas · Human Serome Atlas

HEMK1

MTRF1L release factor glutamine methyltransferase

Also known as: HEMK1_HUMAN, MTQ1

Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene

Protein identityUniProt · HPA

UniProt accession: Q9Y5R4
Gene: HEMK1
Ensembl: ENSG00000114735
Chromosome: 3
Canonical length: 338 aa
Protein class: Enzymes, Predicted intracellular proteins

OverviewNCBI Gene

Enables peptide chain release factor N(5)-glutamine methyltransferase activity. Predicted to be involved in translational termination. Located in mitochondrion. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

338 residues, UniProt reviewed canonical sequence.

>Q9Y5R4|HEMK1
     1  MELWGRMLWA LLSGPGRRGS TRGWAFSSWQ PQPPLAGLSS AIELVSHWTG VFEKRGIPEA
    61  RESSEYIVAH VLGAKTFQSL RPALWTQPLT SQQLQCIREL SSRRLQRMPV QYILGEWDFQ
   121  GLSLRMVPPV FIPRPETEEL VEWVLEEVAQ RSHAVGSPGS PLILEVGCGS GAISLSLLSQ
   181  LPQSRVIAVD KREAAISLTH ENAQRLRLQD RIWIIHLDMT SERSWTHLPW GPMDLIVSNP
   241  PYVFHQDMEQ LAPEIRSYED PAALDGGEEG MDIITHILAL APRLLKDSGS IFLEVDPRHP
   301  ELVSSWLQSR PDLYLNLVAV RRDFCGRPRF LHIRRSGP

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against HEMK1 can act on the native protein depends on physical access: surface and secreted proteins are reachable by circulating antibodies, intracellular proteins usually are not.

Antibody reachability: Intracellular
Secreted: No
Transmembrane segments: 0
Mean surface accessibility (rSASA): 0.28
Highest tissue expression: 28 nTPM

Expression across tissuesHPA

Tissue

choroid plexus: 28 nTPM
testis: 24 nTPM
liver: 23 nTPM
salivary gland: 20 nTPM
kidney: 20 nTPM
pancreas: 19 nTPM

Single-cell type

late spermatids: 222 nCPM
early spermatids: 177 nCPM
late primary spermatocytes: 67 nCPM
paneth cells: 35 nCPM
ovarian stromal cells: 33 nCPM
hepatic stellate cells: 32 nCPM

Immune cell

basophil: 25 nTPM
plasmacytoid DC: 22 nTPM
memory B-cell: 20 nTPM
gdT-cell: 19 nTPM
naive B-cell: 18 nTPM
naive CD8 T-cell: 17 nTPM

Brain region

choroid plexus: 20 nTPM
white matter: 12 nTPM
midbrain: 11 nTPM
medulla oblongata: 11 nTPM
spinal cord: 10 nTPM
basal ganglia: 9.7 nTPM

Genetic constraint and essentialitygnomAD · DepMap

Does the body need this protein intact? Low LOEUF or a strong DepMap dependency means loss or blockade of the protein is likely to be felt.

gnomAD LOEUF (loss-of-function intolerance): 1.03
gnomAD pLI: 0
gnomAD missense Z: 0.53
DepMap mean gene effect: 0.03
DepMap dependency class: none

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 4% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Molecular functions

DNA binding
protein-glutamine N-methyltransferase activity
peptide chain release factor N(5)-glutamine methyltransferase activity

Cellular components

mitochondrion

Protein domainsUniProt · Pfam · InterPro

DNA methylase, N-6 adenine-specific, conserved site
Methyltransferase small domain
S-adenosyl-L-methionine-dependent methyltransferase superfamily
Methyltransferase small domain
N4/N6-methyltransferase, Type III restriction-modification enzyme EcoPI Mod subunit-like
Methyltransferase HemK-like
Release factor glutamine methyltransferase
Release factor glutamine methyltransferase, N-terminal domain
Protein N5-glutamine methyltransferase
PrmC N-terminal domain

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads HEMK1 as an antibody target. Whether an autoantibody or antibody against HEMK1 could matter depends on whether native HEMK1 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

HEMK1 is annotated as predominantly intracellular. Intracellular proteins are common autoantibody markers, becoming visible to the immune system after cell injury or altered processing, but are usually markers of disease rather than direct drivers.

Annotation status

The present source text does not explicitly label HEMK1 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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